Not a homwork problem, Fresnel Equations

1. The problem statement, all variables and given/known data
I was just curious, I know you can derive the critical angle using Snell's law..but could you use it using the Fresnel Equations of reflection, both of them?

## R=1 ## at the critical angle because ## cos(\theta_t) =0 ## since ## \theta_t=90 \, degrees ##. I think it is necessary to use Snell's law to compute the critical angle ## \theta_i=\theta_c ##. For ## \theta_i ## greater than the critical angle, ## \theta_t ## does not exist. ## \\ ## Note: In your very first equation of part 3, I think the first "theta-t" should be a "theta-i". ## \\ ## Additional note: To get Latex, you need to put " ## " on both sides of the expression.